Reduce usage of WebString::data

public/platform/WebString.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 60 matching lines @@
 
     WEBKIT_EXPORT void reset();
     WEBKIT_EXPORT void assign(const WebString&);
     WEBKIT_EXPORT void assign(const WebUChar* data, size_t len);
 
     WEBKIT_EXPORT bool equals(const WebString& s) const;
 
     WEBKIT_EXPORT size_t length() const;
     WEBKIT_EXPORT const WebUChar* data() const;
 
+    // Caller must check bounds.
+    WEBKIT_EXPORT WebUChar at(unsigned) const;
+
     bool isEmpty() const { return !length(); }
     bool isNull() const { return !m_private; }
 
     WEBKIT_EXPORT WebCString utf8() const;
 
     WEBKIT_EXPORT static WebString fromUTF8(const char* data, size_t length);
     WEBKIT_EXPORT static WebString fromUTF8(const char* data);
 
     template <int N> WebString(const char (&data)[N])
         : m_private(0)
@@ skipping 61 matching lines @@
 
     template <class UTF8String>
     static WebString fromUTF8(const UTF8String& s)
     {
         return fromUTF8(s.data(), s.length());
     }
 #endif
 
 private:
     void assign(WebStringPrivate*);
+
     WebStringPrivate* m_private;
 };
 
 inline bool operator==(const WebString& a, const WebString& b)
 {
     return a.equals(b);
 }
 
 inline bool operator!=(const WebString& a, const WebString& b)
 {
     return !(a == b);
 }
 
 } // namespace WebKit
 
 #endif